Clock Animation Crank Mechanism for Smooth Large-Amplitude Motion

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Solution Overview

Problem

Existing timepiece animation mechanisms suffer from aesthetics issues due to perpendicular axes, jerky movements, limited amplitude, and negative impacts on chronometry, particularly with abrupt accelerations and decelerations, and inability to drive elements in planes not parallel to the dial.

Innovation Solution

A watch movement mechanism that transforms unidirectional rotary motion into alternating movements using a crank, drive pinion, and connecting rod system, allowing for smooth, large-amplitude movements in planes parallel to the dial, with optional angular movements around a shaft, and incorporating a speed regulator to minimize acceleration effects.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If a perpendicular axis is used to drive the animation, then the animation can be driven, but the aesthetics are spoiled and significant accelerations occur

Engineering Contradiction:
ImproveaccelerationVSAvoidaesthetics
Core Design Contradiction:
SpeedVSShape

Solution Approach 1:

The invention changes the orientation of the animation axis from perpendicular to the dial plane to parallel with the dial plane. This dimensional reorientation eliminates the aesthetic damage caused by visible perpendicular axes while maintaining the animation function through a different spatial configuration of the driving mechanism.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The invention employs a crank-connecting rod mechanism that transforms uniform rotational motion into reciprocating motion with controlled acceleration and deceleration phases. This dynamic transformation smooths out the abrupt accelerations inherent in direct perpendicular-axis drive mechanisms, creating more natural-looking animation movements.

Inventive Principle:
Principle #15Dynamics

2Length of moving object

If a toothed cam and half-heart mechanism is used, then animation can be produced, but the amplitude of movements is very limited

Engineering Contradiction:
Improveamplitude of movementVSAvoidmechanism complexity
Core Design Contradiction:
Length of moving objectVSDevice complexity

Solution Approach 1:

The invention changes the motion parameters by using a crank mechanism with adjustable eccentricity and a connecting rod of optimized length. This allows the amplitude of animation movements to be significantly increased compared to the fixed-amplitude half-heart mechanism, while maintaining reasonable mechanical complexity through well-established kinematic principles.

Inventive Principle:
Principle #35Parameter changes

3Speed

If a toothed cam mechanism is used, then animation can be driven, but the moving elements move jerkily and undergo abrupt accelerations and decelerations

Engineering Contradiction:
Improvesmoothness of movementVSAvoidoperation smoothness
Core Design Contradiction:
SpeedVSEase of operation

Solution Approach 1:

The crank-connecting rod mechanism inherently provides smooth motion transitions by transforming uniform rotation into reciprocating motion with continuous velocity changes. The connecting rod acts as a dynamic element that absorbs and distributes the acceleration forces, eliminating the jerky movements characteristic of direct cam-follower mechanisms.

Inventive Principle:
Principle #15Dynamics

4Power

If force is taken from the escapement fork pivot, then animation can be produced, but the chronometry is negatively affected

Engineering Contradiction:
Improvepower for animationVSAvoidchronometric accuracy
Core Design Contradiction:
PowerVSReliability

Solution Approach 1:

The invention uses the mainspring motor to serve dual functions: driving both the timekeeping mechanism and the animation mechanism through a common power source. This eliminates the need to extract power from the escapement fork, thereby preserving chronometric accuracy while still providing sufficient power for animation through the main drive train.

Inventive Principle:
Principle #6Universality (Multi-functionality)

5Adaptability or versatility

If existing mechanisms are used, then animation can be driven, but they cannot drive elements in planes not parallel to the dial

Engineering Contradiction:
Improvemovement plane flexibilityVSAvoidmechanism flexibility
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The invention enables animation elements to move in planes parallel to the dial by reorienting the crank axis horizontally rather than perpendicularly. This dimensional change in the mechanism's orientation provides the versatility to drive animations in previously inaccessible planes without significantly increasing overall mechanism complexity.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The mechanism enhances the aesthetics and functionality of timepiece animations by providing smooth, large-amplitude movements without jerky actions, maintaining chronometric accuracy, and allowing for compact designs while enabling movements in planes parallel to the dial.

Implementation Method 1

said crank comprises a drive pinion and a pin, said drive pinion being pivoted on a fixed part of the mechanism, driven in unidirectional rotation by said motor of the watch movement and carrying said pin around which pivots a first end of the connecting rod, said pin being eccentric with respect to the axis of rotation of said drive pinion and parallel to this axis

Methodology Applied
Scientific EffectEccentric mechanism: Eccentric

Data Source

PatentEP3239786B1Mechanism for driving an animation of a clock movement
Publication Date: 2021.09.08 VAN CLEEF & ARPELS SA
  • EP3239786B1 patent drawingFigure 1
  • EP3239786B1 patent drawingFigure 2~3
  • EP3239786B1 patent drawingFigure 4a~4b

AI summary

The mechanism for transforming a unidirectional rotary movement into an alternating movement for driving an animation of a watch movement according to the invention comprises a crank (1, 2) pivoted on a fixed part of the mechanism and able to be driven in unidirectional rotation by a motor of the watch movement, said crank driving a first end of a connecting rod (3), the second end of this connecting rod (3) being capable of driving a moving part of the animation.